As an instrument device to be mounted on a vehicle or the like of the related art, configurations shown in Patent Document 1 or Patent Document 2 are known. The instrument devices in these Patent Documents include an instrument device including a display panel arranged on the front side of a needle-type indicating instrument such as a speedometer or a tachometer, a circuit board formed of a hard material on which the indicating instrument is mounted, a middle case formed of a resin material, arranged on the front side of the circuit board and configured to place the display panel, an upper case arranged on the front side of the middle case and including a see-through panel member formed of a resin material which allows at least a front surface to be seen through and a facing panel member configured to partition a display area of the display panel, and a lower case formed of a resin material and configured to cover the middle case and the circuit board.
In this case, in order to achieve a simple assembly of the instrument device, for example, a configuration in which operations such as assembly or disassembly is facilitated in comparison with a screw-tightening operation using a screw, which is a separately provided part, by providing claw-shaped hook portions on resilient arm strips and frame-shaped engaging portions configured to engage the hook portions of the resilient arm strips so as to be detachably attachable instead of fixing means on the basis of screw tightening is known.    Patent Document 1: JP-A-2001-174292    Patent Document 2: JP-A-2008-75696